I do agree with the theory of garbage in/garbage out, but many use these headphones to reduce or eliminate the drone of the airplane as well as the blabbermouths talking in nearby rows.

That said, I could not justify buying the super-high end shures but can certainly justify spending $100 bucks for some peace and quiet.

Sometimes, when I feel the need to be really isolated, I wear my Bose over the inserted headphones. The only noise you hear then is the sound of your beating heart...which always reminds me that I should exercise more.